Brake is on

Im using the standard DFGT setup and ive noticed in the control setup screen that my brake is flickering on and off. Its only a slight slight bit would this make a difference in game? i cant seem to find a way to 'zero' the settings or try and recalibrate the pedals. If i lift the pedal slighty it goes to 0% and when i press it again and lift off it goes back to flickering. Is this a software issue or do i need to open up the unit?